Electric brakes or slowing down devices



June 19, 1956 P. E. BESSIEZRE 2,751,513

ELECTRIC BRAKES OR SLOWING DOWN DEVICES Filed Aug. 16, 1954 nitcd States Patent 01 2,751,51 Patented June 19, 1956 ice 2,751,513 ELECTRIC BRAKES R SLOWIN G DOWN DEVICES Pierre Etienne Bessiere, Paris, France, assignor to Compagnie Telma, Paris, France, a French society Application August 16, 1954, Serial No. 449,870 Claims priority, application France August 19, 1953 3 Claims. (Cl. 310-93) The present invention relates to electric brakes or slowing down devices in which the braking or slowing down eifect is obtained by means of Foucault currents created in a rotor, preferably of a magnetic material, rigid with the shaft to be braked and rotating in the electromagnetic field of several inductors constituted by two sets of electro-magnets fixed with respect to the frame of the vehicle which is to be braked and disposed on either side of said rotor. This invention is concerned with brakes of this type in which the rotor includes two parallel discs rigidly fixed by their respective central portions to said shaft and located at a distance from each other.

The object of the present invention is to provide a brake device of this kind which is better adapted to meet the requirements of practice than those used up to the present time.

According to my invention, the peripheral portions of said rotary discs are provided with means for preventing relative displacements of said disc peripheral portions away from each other, but capable of leaving said respective disc portions free to move toward each other.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which:

Fig. l is an axial sectional view of a braking device made according to the invention.

Fig. 2 is a sectional view on the line II-II of Fig. 1, the rotor being removed.

Fig. 3 is a perspective detail view.

The braking device illustrated by the drawings includes a rotor constituted by two discs, 1a and 1b, of a magnetic metal fixed on a shaft 2 driven by the shaft to be braked, or rigid therewith.

This rotor is movable with respect to inductor means fixed to a frame mounted on the vehicle to be braked. Said inductor means are constituted by two units disposed respectively on opposite sides of the rotor.

Every inductor unit is constituted by a set of electromagnets carried by an annular disc 3 coaxial with shaft 2 and fixed on the bearings 13 of said shaft by means of radial arms 6.

The cores 5 of the electro-magnets are integral with annular disc 3, from which they project toward rotor la-1b. Windings 4 are formed on said cores 5.

Radial arms 8 connect the outer periphery of annular disc 3 with an outer ring 9, the rings 9 of the two respective inductor units being secured together.

Cooling of the inner ends of windings 4 is obtained by circulating, along said winding ends, air streams which enter through the intervals 12 between radial arms 6, flow along said winding ends and pass between the two discs 1a and 1b of the rotor which are provided, on the sides thereof facing each other, with radial fins 14a and 14b acting as fan blades. Said air streams finally ecape from the periphery of the rotor in directions at right angles to shaft 2.

This air circulation serves to cool not only the inner ends of windings 4 but also the inner faces of discs 1a and 111.

According to my invention, the rotor discs and 1b are provided with means, located in the vicinity of the peripheries of said discs, and adapted to prevent relative displacements of said respective disc peripheral portions away from each other but leaving said respective disc portions free to move toward each other.

Such means are illustrated by Fig. 3. They consist in abutments 15a and 15b carried by fins 14a and 14b respectively, said abutments being offset in opposed direction with respect to the respective fins which carry them so that every abutment 15a carried by the fin 14a is located between the other disc 1b and a corresponding abutment 15b carried by the find 14b of said other disc. Thus, when these abutments come into contact with each other they prevent the peripheral portions of discs 1a and 11; from moving away from each other, but they do not prevent these peripheral disc portions from moving toward each other.

It is pointed out that such abutment means avoid the necessity of drilling holes in discs 1a and 1b.

It will be readily understood that when discs 1a and 1b are cooled, for instance as above explained, the opposed faces of each of said discs are at different temperatures and therefore these discs tend to deform either on one direction or on the other. When the discs deform toward each other, there is no danger of deterioration because these discs can hardly come into contact with each other. But when said discs move away from each other, they may very quickly come into contact with the cores 5 of the electro-magnets which is of course undesirable. This must be prevented. Deformation of the discs toward each other may be permitted because they are not so detrimental and on the other hand, to prevent such movements would involve stresses in the discs which would be detrimental of a good solidity of the whole.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efiicient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An electric brake for braking a shaft with respect to a frame, which comprises, in combination, a rotor rigid with said shaft, two sets of electro-magnets carried by said frame and disposed on either side of said rotor, to form an electromagnetic field in which said rotor is located whereby Foucault currents are produced when this rotor is turning inside said field, said rotor being constituted by two discs both fixed at their respective central portions on said shaft but extending substanially parallel to each other, and means carried by the peripheral portions of said two discs respectively for preventing said peripheral portions from moving away from each other while leaving them free to move toward each other.

2. A brake according to claim 1 in which said means include projections carried by the inner faces of said discs and extending in directions at least substantially at right angles to said discs, and interlocking abutments carried by said projections so that every abutment carried by a projection rigid with one disc is interposed between an abutment carried by the corresponding projection of the other disc and said last mentioned disc.

3. A brake according to claim 1 in which said discs include solid annular portions and said means are located farther from the axis of said shaft than the peripheries of said annular portions.

References Cited in the file of this patent UNITED STATES PATENTS 

